Diagnostic lenses such as fundoscopic and gonioscopy lenses are commonly used for various types of ocular evaluation. These types of lenses are specifically designed to allow different areas of the retina and other portions of the eye to be evaluated and are typically used to review the posterior, equatorial and anterior areas of the retina, the ora serrata, the anterior chamber, the posterior chamber, the vitreous chamber, and more. Such lenses are useful because they allow an optometrist, ophthalmologist, or other eye care professional to examine the interior of the eye for potential ocular defects and/or disease. Because the pupil of the eye is small and the eye is essentially spherical, it is difficult to visually examine various interior portions of the eye with a normal lens. Thus, it is difficult to examine many portions of the eye such as peripheral portions of the vitreous chamber and the retina. In order to allow viewing of substantially the entire vitreous chamber and retina of the eye, as well as other areas, diagnostic lenses such as gonioscopy lenses and fundus contact lenses were developed.
Known prior art diagnostic lenses, such as the known gonioscopy lenses and multi-mirrored fundus contact lenses, typically include a concave central lens located at one end portion thereof and a plurality of mirrors positioned around the central lens which are encased in a funnel-shaped cone and protected by a planar glass viewing surface. The central viewing lens is utilized to assess the posterior 30.degree. of the retina. Lateral or adjacent to the central lens are a plurality of mirrors, typically three mirrors, which are spaced 120.degree. apart and are mounted at different angles of inclination to the funnel-shaped cone to allow different areas of the eye to be evaluated. Typically, these mirrors are angled at 59.degree., 67.degree. and 73.degree.. These mirrors reflect light at different angles so that different parts of the eye can be examined. In order to identify a specific mirror, manufacturers of these lenses have universally assigned three sizes and shapes to the mirrors so that the users thereof can quickly and easily identify each mirror and its associated angular inclination.
Other prior art diagnostic lenses of this type are formed from a solid piece of clear plastic of a specific polymer or acrylic resin composition wherein surfaces are shaped and cut at different angles of inclination such that the natural refraction of light through these angled surfaces will likewise allow different parts of the eye to be examined. These cut and angled surfaces function in the same manner as the mirrors described above and such surfaces are also differently sized and shaped for easy identification.
The selection and position of the specific mirror or angled surface to be utilized during an evaluation depends upon that portion of the eye which needs to be evaluated. The selected mirror or surface is then placed opposite the area to be evaluated. For example, if the 12 o'clock position of the peripheral retina needs to be evaluated and a mirrored lens is being utilized, the median sized mirror which is angled at 67.degree. can be positioned at the 6 o'clock position of the retina so as to view the affected area. Each mirror or angled surface allows the user to inspect and evaluate different portions of the eye based upon the shape and inclination of such mirrors or angled surfaces.
Because the mirrors or surfaces are inclined at different angles and are typically circumferentially spaced apart, it is necessary to rotate the known prior art lenses a full 360.degree. in order to examine the entire retina or other portions of the eye. Manipulation and positioning of the appropriate mirror or surface at the appropriate location relative to the retina is generally accomplished by manually rotating the entire lens device on the eye of the patient until the selected mirror or surface is located in the proper position. This orientation is obtained by simply rotating the lens between the forefinger and thumb of the user so that the lens is 180.degree. opposite the area to be evaluated. Rotation of the lens can be accomplished with one or two hands depending upon the practitioner. The user, when using a prior art lens of this type, must therefore coordinate the use and manipulation of the slit-lamp biomicroscope which is used in conjunction with these types of lenses with manual rotation of the gonioscopy or other diagnostic lens on the eye of the patient.
Although co-pending U.S. patent application Ser. No. 09/022,214, now U.S. Pat. No. 5,841,510, is directed to several embodiments of a rotatable diagnostic lens for ocular evaluation wherein any number of mirrors associated with such lens devices can be rotated separate and apart from the overall device, it is also desirable to provide an apparatus and method for converting existing conventional non-rotatable diagnostic lens to a rotatable type lens which will enable a user to not only continue to use existing lens equipment, but which will enable the user to more easily and freely manipulate the mirrors associated with such lens during ocular evaluations.